In 2018, the American military spent $480 million on 100,000 prototype augmented-reality goggles from Redmond to see how they could help soldiers train for and fight in combat. The Integrated Visual Augmentation System (IVAS) project was expanded when the Army decided it wanted the Windows giant to make custom, battle-ready AR headsets in a ten-year deal worth up to $22 billion.

However, the project was delayed and might make an appearance this year. But the US Dept of Defense's Office of the Inspector General (OIG) cast some doubt on whether it was worth it.

"Procuring IVAS without attaining user acceptance could result in wasting up to $21.88 billion in taxpayer funds to field a system that soldiers may not want to use or use as intended," the Pentagon oversight body wrote in an audit report this month.

The heavily redacted report did not reveal soldiers' responses to the prototype testing, but it said feedback from surveys showed "both positive and negative user acceptance."

The Army plans to purchase 121,500 IVAS units from Microsoft while admitting that "if soldiers do not love IVAS and do not find it greatly enhances accomplishing the mission, then soldiers will not use it," the report disclosed.

A Microsoft spokesperson said that it was developing IVAS to be a transformational platform that will deliver enhanced soldier safety and effectiveness."

Assistant secretary of the Army for acquisition, logistics and technology, Douglas Bush said the $21.88 billion was double what the military would likely at most spend, and was a worst-case scenario figure.

"This is a contract ceiling that includes all possible hardware, components, and services over a ten-year period at the worst possible pricing structure. Less than half of this total is possible for the US Army. This total includes all possible sales to all sister services, foreign military sales, and all maximised service contracts," he wrote.